Cotton-like knitted fabric, polyester filament and production method thereof

ABSTRACT

The present invention provides a cotton-like knitted fabric, a polyester filament and a production method. The fabric is a weft-knitted fabric obtained by material containing at least above 45% by weight of polyester filaments; the pore area distribution of the fabric is centered on 6000 to 22000 μm2 and has a statistical variability of above 2a, and the coefficient of variation of the pore area is greater than 40%. The polyester filament is formed from alternatingly arranged twist regions in a false-twist direction and twist regions in an opposite direction, wherein the twist regions in the false-twist direction have an average length of less than 0.3 cm, a coefficient of variation of length of above 60%, a diameter that is 30% to 70% of the diameter of the twist regions in the opposite direction, and a total length that is 20.0% to 40.0% of the total length of the polyester filaments.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Phase application of PCT/CN2015/097077, filedDec. 11, 2015, which claims priority to Chinese Patent Application No.201410763413.5, filed Dec. 12, 2014, the disclosures of each of theseapplications being incorporated herein by reference in their entiretiesfor all purposes.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a cotton-like knitted fabric, apolyester filament and a production method thereof, and in particular toa cotton-like knitted fabric suitable for manufacturing T-shirts and apolyester filament used as a raw material thereof.

BACKGROUND OF THE INVENTION

At present, the majority of commercially available knitted T-shirts aremainly made of cotton fibers. In comparison with T-shirts made ofchemical fibers, such knitted T-shirts are highly soft and hydroscopic.However, when in use, the disadvantages of the cotton products aregradually revealed. For example, they exhibit low air permeability andfast-drying performance. In addition, with the continuous increase inmarket demands, the cotton fibers are somewhat in short supply.Furthermore, since the cultivation of cotton is easily vulnerable toclimate changes, the supply of cotton raw material is very unstable.Therefore, it is very necessary to replace cotton fibers with chemicalfibers to produce cotton-like knitted fabrics which have the advantagesof cotton and may overcome the disadvantages of cotton.

At present, there are many researches on the cotton-like knitted fabric.For example, the Patent Document CN103898670A has disclosed acotton-like knitted fabric and a production method thereof, wherein thecotton-like knitted fabric is obtained by jointly knitting purepolyester staple yarns, polyester-cotton staple yarns and spandex yarns.The obtained fabric is processed by high-temperature alkali deweightingto achieve excellent softness and cotton-like effect, the hydroscopicand fast-drying performance is greatly improved, and the defect that afabric made of chemical fibers is stuffy when worn is overcome. However,the high-temperature alkali deweighting will dissolve hairs on thesurface of the fabric and reduce the hairiness of the fabric. Moreover,due to the high processing temperature and the use of caustic soda, thepurpose of saving energy and reducing emission cannot be realized, andthe processing cost is increased. In addition, since the majority of thematerials are staple fibers, the air permeability and bursting strengthof the fabric will be affected.

For another example, the Patent Document CN102517775A has disclosed ahygroscopic and exothermic super cotton-like knitted fabric with ajacquard air layer, which is formed from blended yarns made of Porelfibers (capillary polyester long fibers) and cellulosic fibers, with thecontent of the cellulosic fibers in the blended yarns being 50% to 60%.Thus, the resulting knitted fabric is very excellent in cotton-likeeffect and hydroscopic and fast-drying performance. However, since theused Porel fibers belong to special functional fibers, the relativelyhigh content of the Porel fibers increases the product cost.

In addition, at present, there are technologies for performingfalse-twisting on polyester filaments in order to allow yarns to exhibita certain natural fiber style. For example, the Patent DocumentCN103603113A has disclosed a textured yarn obtained by fusing andfalse-twisting polyester filaments, which is soft and has aconcavo-convex feeling on the surface when touched. A fabric formed fromsuch a textured yarn has a gritty and hollow-out texture. However, sincetwist regions in a false-twist direction of the yarn have a too smallcoefficient of variation, the obtained fabric does not have theappearance and touch feeling of cotton products although it has auniform pore area distribution and a high glossiness. For anotherexample, the Patent Document JP2000-303287 has disclosed apartially-fused polyester yarn, where twist portions in a false-twistdirection, twistless crinkled portions and twist portions in a untwistdirection are alternatively arranged. On the surface of the yarn, thereare basically no nubs, and the glossiness is reduced, so that theheterogeneity and roughness of the surface of a linen fabric are solved.However, it is difficult to control the presence of twistless crinkledportions between the twist portions in the false-twist direction and theuntwist portions in the untwist direction, and the processing iscomplicated and high in cost. Moreover, the obtained fabric feels likelinen and is unable to be compared with cotton products in touch feelingand appearance.

SUMMARY OF THE INVENTION

In view of the above problems, an objective of the present invention isto provide a polyester filament which is simple in processing, soft intouch feeling and high in natural fiber feeling, and a cotton-likeknitted fabric obtained from the polyester filament, which feels likereal cotton and is excellent in air permeability, bursting strength,hydroscopic and fast-drying performance, and ultraviolet resistance.

The present invention includes the following technical solutions.

The present invention provides a cotton-like knitted fabric which is aweft-knitted fabric obtained by material containing at least above 45%by weight of polyester filaments; and, the pore area distribution of thefabric is centered on 6000 to 22000 pmt and has a statisticalvariability of above 2σ, and the coefficient of variation of the porearea is greater than 40%.

The present invention provides a polyester filament which is formed fromalternatingly arranged twist regions in a false-twist direction andtwist regions in an opposite direction, wherein the twist regions in thefalse-twist direction have an average length of less than 0.3 cm, acoefficient of variation of length of above 60%, a diameter that is 30%to 70% of the diameter of the twist regions in the opposite direction,and a total length that is 20.0% to 40.0% of the total length of thepolyester filaments.

The cotton-like knitted fabric of embodiments of the present inventionhas the same pore area distribution and the same appearance as thecotton-containing products. Meanwhile, since the polyester filament isused as the main raw material, compared with a product made of staplefibers, the cotton-like knitted fabric is excellent in air permeability(JISL1096-2010 standard method A: 75 to 150 cm³/cm²/s) and burstingstrength (JISL 1096-2010 standard: above 700 kpa), and compared with acotton-containing product, it is excellent in hydroscopic andfast-drying performance (Corker method: the residual moisture after 60min is below 10%). Moreover, since the non-uniform diameter of thepolyester filaments used in the present invention improves the diffusereflection effect of the fabric and the polyester itself has anultraviolet-resistant aromatic ring molecular structure, the fabric isexcellent in ultraviolet resistance (Australian standardAS/NZS4399-1996: the value of UPF is above 45). The fabric of thepresent invention is particularly suitable for manufacturing T-shirts orthe like. In addition, the method for processing the polyester filamentof the present invention is simple and easy, and provides for soft touchfeeling and high natural fiber feeling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a polyester filament in the length directionaccording to an embodiment of the present invention, in which: 1: twistregion in a false-twist direction; 2: twist region in an oppositedirection; and, 3: twist region in the false-twist direction; and

FIG. 2 is a flowchart of processing the polyester filament according toan embodiment of the present invention, in which: 4: polyesterpre-oriented yarn POY; 5: first roller; 6: first hot box; 7: falsetwister; 8: moving sliver; 9: second roller; 10: second hot box; 11:third roller; 12: polyester filament (drawn textured yarn DTY); and, 13:reeling drum.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a knitted fabric which is a weft-knittedfabric obtained by material containing at least above 45% by weight ofpolyester filaments; and, the pore area distribution of the fabric iscentered on 6000 to 22000 μm² and has a statistical variability of above2a, and the coefficient of variation of the pore area is greater than40%.

Considering that the polyester filament among the chemical fibers issimple in processing and low in cost and the polyester filament fabricis excellent in air permeability, bursting strength and otherperformances when compared with a polyester staple fiber fabric, thepolyester filament is used as a material in the present invention. Inaddition, considering that the weft-knitting stitch has betterflexibility, softness and comfort than other types of stitches, theweft-knitting stitch is used as a knitting stitch in the presentinvention.

In the material of an embodiment of the present invention, if thecontent of polyester filaments is less than 45%, the pores of the fabricwill be reduced and the air permeability will be degraded, and as aresult, the wearing comfort will be influenced. Furthermore, theappearance of cotton-containing products cannot be realized, and thepore area distribution is not centered within 6000 to 22000 μm².

In an embodiment of the present invention, the pore area distribution ofthe fabric is centered within 6000 to 22000 μm² and has a statisticalvariability of above 2σ, the coefficient of variation (C.V) of the porearea is greater than 40%, and the fabric has the same appearance ascotton-containing products. When the pore area distribution of thefabric is centered less than 6000 μm², it is indicated that the fabrichas smaller pores and higher compactness and does not feel like cottondue to too stiff touch feeling. In addition, if the fabric is toocompact, the fabric has reduced air permeability and lower flexibility,and the wearing comfort is greatly degraded. When the pore areadistribution of the fabric is centered more than 22000 μm², it isindicated that the fabric has larger pores and is too loose, and as aresult, the requirements on slenderness and thickness of thecotton-containing products cannot be met. If the pore area has astatistical variability of within 2σ and a coefficient of variation ofthe pore area of the fabric is less than 40%, it is indicated that thefabric has uniform pores, low concavo-convex feeling and high glossiness(i.e., feels like chemical fibers), which are contrary to the lowglossiness of the cotton-containing products.

In order to make the pore distribution of the fabric closer to that ofthe cotton-containing products, the content of the polyester filamentsof the present invention is preferably 100%. If the content of polyesterfilaments is higher, the distribution of the pore area is morenon-uniform, and the appearance and touch feeling of the pure cottonstaple fiber fabric may be more imitated. Of course, in the presentinvention, polyester staple yarns, natural fiber staple yarns or thelike may be knitted with the polyester filaments of the presentinvention to realize the cotton-like effect.

Preferably, the present invention provides a polyester filament which isformed from alternatingly arranged twist regions in a false-twistdirection and twist regions in an opposite direction, wherein the twistregions in the false-twist direction have an average length of less than0.3 cm, a coefficient of variation of length of above 60%, a diameterthat is 30% to 70% of the diameter of the twist regions in the oppositedirection, and a total length that is 20.0% to 40.0% of the total lengthof the polyester filaments. Such a polyester filament looks like acotton spun yarn in terms of appearance and various performances. Here,the twist regions in the false-twist direction are twisted portions ofthe yarn, and the twist regions in the opposite direction are untwistedportions of the yarn.

With regard to the polyester filament of the present invention, if twistregions in the false-twist direction have an average length of greaterthan 0.3 cm, the proportion of the twist regions in the false-twistindirection in the length direction of the yarn will be increased, andthe yarn will become thinner and stiffer. Although the slenderness ofthe obtained fabric is enhanced, the fabric tends to become stiffer whentouched.

With regard to the polyester filament of the present invention, if thecoefficient of variation of length (C.V) is less than 60%, the pore areadistribution of the obtained fabric tends to become uniform, and it ispossible to reduce the cotton-like effect, so that it is difficult toobtain the cotton-like appearance.

With regard to the polyester filament of the present invention, if aratio of the diameter of the twist regions in the false-twist directionto the diameter of the twist regions in the opposite direction issmaller, that is, there is a larger difference between the diameter ofthe twist regions in the false-twist direction and the diameter of thetwist regions in the opposite direction, the fabric has a morenon-uniform pore area distribution and an appearance more similar to thecotton-containing products. However, if the ratio of the diameter of thetwist regions in the false-twist direction to the diameter of the twistregions in the opposite direction is less than 30%, that is, there is atoo large difference between the diameter of the twist regions in thefalse-twist direction and the diameter of the twist regions in theopposite direction, it is possible to result in too large pores of thefabric, decrease the compactness and thus influence the cotton-likeeffect. If the ratio of the diameter of the twist regions in thefalse-twist direction to the diameter of the twist regions in theopposite direction is greater than 70%, that is, there is a smalldifference between the diameter of the twist regions in the false-twistdirection and the diameter of the twist regions in the oppositedirection, it is possible to result in too uniform pore distribution ofthe fabric, and thus influence the cotton-like appearance effect. Inaddition, it is also possible to result in a smaller diameter of thetwist regions in the opposite direction of the yarn, so that thesoftness of the fabric is decreased.

In addition, with regard to the polyester filament of the presentinvention, if a ratio of the total length of the twist regions in thefalse-twist direction to the total length of the polyester filament issmaller, better fluffiness and softness may be endowed to the fabric. Ifthe proportion of the twist regions in the false-twist direction is lessthan 20%, it is possible to decrease the slenderness even if thefluffiness and softness of the fabric are improved, so that the balancebetween the slenderness and the softness of cotton products cannot berealized. However, if the proportion of the twist regions in thefalse-twist direction is greater than 40%, it is possible to decreasethe softness even if the slenderness of the fabric is increased, and thebalance between the slenderness and the softness of the cotton productcannot also be realized.

The polyester filament of an embodiment of the present invention has atotal fineness of 56 to 220 dtex. When the total fineness is less than56 dtex, the fabric formed from the polyester filament has a smallerpore area, a reduced pore area difference and a smaller thickness, andthe cotton-like appearance effect and the touch feeling are likely to bedecreased. However, when the total fineness is greater than 200 dtex,the fabric formed from the polyester filament has larger pores, a toolarge thickness and poor cotton-like effect, and the compactness offull-cotton products may not be realized.

The polyester filament of the present invention preferably has amonofilament fineness of less than 1.3 dtex. If the monofilamentfineness is greater than 1.3 dtex, it is possible to influence thesmoothness of the fabric and decrease the cotton-like effect.

The fabric of an embodiment of the present invention is obtained byknitting a single polyester filament or jointly knitting two polyesterfilaments, refining, dying, sizing and other processes. In this way, thebalance between the compactness and the pore distribution of the fabricmay be ensured. For example, if polyester filaments having a totalfineness of 56 to 100 dtex are to be used, two polyester filaments maybe fed for knitting. For another example, if polyester filaments havinga total fineness of 100 to 200 dtex, a single polyester filament may befed for knitting.

To make the touch feeling of the fabric similar to cotton products, thecotton-like fabric of the present invention is preferably obtained byfluffing. The equipment for fluffing is not specifically limited, andmay be a sanding machine from Sperrotto in Italy, with a speed of 5 to30 m/min, a tension of 0.4 to 0.6 MPa and a mesh of 160# to 240#.

Preferably, the cotton-like knitted fabric of the present invention hasa bending rigidity (B) of 0.015 to 0.045 N·cm²/cm, a surface roughness(SMD) of 3 to 6μ, and a compression energy (WC) of 0.2 to 0.8 N·cm/cm².These performances are consistent with those of the commerciallyavailable full-cotton T-shirt fabric. The present invention solves thetechnical difficulty that the bending rigidity and the compressionenergy of the common polyester filament cotton-like fabric cannot meetthe requirements for the cotton products even if its surface roughnessis the same as the cotton-containing products. The bending rigidity hererefers to the stiffness and flexibility of the fabric and reflects theslenderness of the fabric. If the bending rigidity has a larger value,the fabric is stiffer. The cotton products have a certain flexibilityand slenderness. The surface roughness refers to the flatness of thesurface of the fabric. If the surface roughness has a smaller value, thefabric is smoother; or otherwise, the fabric is rougher. The compressionenergy refers to the fluffiness of the fabric. If the compression energyhas a larger value, the fabric is more fluffy.

With regard to the cotton-like knitted fabric of the present invention,the knitting stitch is not specifically limited. Plain stitch,close-mesh stitch or the like may be used as long as a certaincompactness is endowed to the fabric. The plain stitch is preferred.

The polyester filament of the present invention may be obtained by thefollowing method: leading a polyester pre-oriented yarn POY into a firstroller, then into a first hot box for heating, and finally into a falsetwister, a second roller, a second hot box and a third roller inaccordance with the procedure of FIG. 2 to obtain the finished product,where the temperature in the first hot box is 230° C. to 250° C., andthe D/Y ratio in the step is 1.5 to 2.5. In the above procedure, thespeed is not limited, and may be preferably 300 to 500 m/min forconvenient operation; and, the extension rate is also not limited, andmay be preferably 1.10 to 2.00 for convenient operation.

The polyester pre-oriented yarn POY used in the above procedure may beobtained by a known method in the art, for example, by melt spinningcommercially available polyester chip material. The speed of meltspinning may be set properly, preferably 2500 to 3500 m/min. Thefineness of the obtained polyester pre-oriented yarn POY and the numberof monofilaments are not specifically limited. To obtain the polyesterfilament applicable to the present invention conveniently, the finenessof the polyester pre-oriented yarn POY is preferably 70 to 280 dtex, andthe number of monofilaments is preferably 70 to 208.

In the above processing process, when the temperature in the first hotbox is lower than 230° C., the ratio of the total length of the twistregions in the false-twist direction to the total length of thepolyester filament will be less than 20% even if the average length ofthe twist regions in the false-twist direction may be controlled lessthan 0.3 cm; and the fabric obtained from the polyester filament cannotfeel like real cotton even if its softness is increased and theslenderness is decreased. Moreover, the ratio of the diameter of thetwist regions in the false-twist direction to the diameter of the twistregions in the opposite direction will also be less than 30%, and thedifference in diameter between the two kinds of regions will becomelarger. Thus, although the pore area distribution of the fabric maybecome more non-uniform, the partial pore area of the fabric will be toolarge, so that the same compactness as the cotton products cannot berealized. However, if the temperature in the first hot box is higherthan 250° C., the average length of the twist regions in the false-twistdirection is greater than 0.3 cm, the ratio of the total length of thetwist regions in the false-twist direction to the total length of thefilament will be also greater than 40%, and the fabric obtained from thefilament has a greatly decreased softness although its slenderness isincreased, so that the cotton-like touch feeling cannot also berealized. If the ratio of the diameter of the twist regions in thefalse-twist direction to the diameter of the twist regions in theopposite direction is greater than 70%, the diameter of the twistregions in the opposite direction of the yarn becomes smaller, the yarnis too stiff as a whole, and the cotton-like effect (softness) of thefabric is thus influenced.

To realize the cotton-like effect, the coefficient of variation (C.V) oflength of the twist regions in the false-twist direction of thepolyester filament is to be controlled above 60%. Therefore, in theprocessing process, the D/Y ratio is to be set as 1.5 to 2.5. The D/Yratio here is obtained by dividing the surface speed of stacked discs bythe surface speed of the two rollers. If the D/Y ratio is less than 1.5,the untwist tension is too large, the twist regions in the false-twistdirection are damaged, the distribution in the length direction is toouniform, and the coefficient of variation (C.V) is too small. When thecoefficient of variation (C.V) is less than 60%, the pore areadistribution of the obtained fabric tends to become uniform, thenep-like effect is decreased, and it may be impossible to realize theappearance of the cotton-containing products. However, if the D/Y ratiois greater than 2.5, the untwist tension is too small and the quality ofthe yarn cannot be ensured.

Preferably, the polyester filament of the present invention has afineness of 56 to 220 dtex. If the fineness is less than 56 dtex, thatis, the used raw yarn is thin, in the false-twisting process in thefirst hot box, the excessive fusion and false-twisting phenomenon may becaused due to too thin raw yarn, and it is difficult to untwist thetwist regions in the opposite direction in the untwisting process, sothat the diameter of the twist regions in the opposite direction becomessmaller. As a result, the difference in diameter between the twistregions in the false-twist direction and the twist regions in theopposite direction becomes smaller, the pore area of the formed fabricbecomes smaller, and the difference in the pore area tends to be notobvious, so that it may be impossible to realize the appearance of thecotton-containing products. In addition, it may be possible to make theaverage length of the twist regions in the false-twist direction greaterthan 0.3 cm and the ratio of the total length of the twist regions inthe false-twist direction to the total length of the filament higherthan 40%. Such a polyester filament is relatively stiff, and the formedfabric is difficult to realize the same softness as thecotton-containing products even if its slenderness is increased. If thefineness is greater than 200 dtex, that is, the used raw yarn isrelatively thick, in the false-twisting process in the first hot box,the insufficient fusion phenomenon may be caused due to too thick rawyarn, so that the diameter of the twist regions in the oppositedirection becomes larger and the ratio of the diameter of the twistregions in the false-twist direction to the diameter of the twistregions in the opposite direction may be less than 30%. As a result, thedifference in diameter between the two regions becomes larger, the porearea of the formed fabric becomes larger, and, like thecotton-containing products, the compactness tends to decrease. Inaddition, it is also possible to make the ratio of the total length ofthe twist regions in the false-twist direction to the total length ofthe filament less than 20%, and the formed fabric is difficult torealize the slenderness of the cotton-containing products.

Meanwhile, preferably, the polyester filament of the present inventionhas a monofilament fineness of less than 1.30 dtex. When the temperaturein the first hot box is set as 230 to 250° C. and the D/Y ratio is setas 1.5 to 2.5, and if the monofilament fineness of the finished productpolyester filament is greater than 1.30 dtex, the monofilament finenessof the raw yarn is relatively large. The polyester filament obtainedunder these processing conditions is similar to the cotton yarn inappearance or the like, and the pore distribution of the fabric obtainedfrom the polyester filament is also similar to that of thecotton-containing products. However, since the monofilament fineness isrelatively high, it may be difficult to realize the smoothness of thecotton-containing products.

EMBODIMENTS

Various parameters in the present invention are tested as follows.

(1) Standard Variance of the Pore Area of the Fabric and the Pore AreaDistribution Center Value

{circle around (1)} Preparation of samples: a sample fabric having asize of 20 cm×20 cm and a flat surface is cut off from the fabric.

{circle around (2)} A fabric surface picture of the sample is taken by adigital microscope (KEYENCE) with a 50× lens.

(a) The brightness of the sample is adjusted between ⅓ and ⅔ by abrightness knob on a rotary control board. When the brightness is lessthan ⅓, the exposure rate is too low, the picture of the sample is toodark, and the pores of the sample cannot be recognized. When thebrightness is greater than ⅔, the exposure rate is too high, and thepores of the sample cannot also be recognized.

(b) The lens is adjusted to 50×, and the definition of the sample isadjusted by rotating a focusing knob on an XY platform or a controlboard, so as to ensure the clarity of the pores of the sample. When themagnification of the lens is too low, the appearance area of the poresof the sample is too small, and the precision of subsequent brightnessextraction and pore area will be influenced. However, when themagnification of the lens is too high, the total area of the takenpicture of the sample is too small, the number of pores is less, and theactual distribution precision of the pore area is influenced.

(c) The picture is saved, and the area of the fabric in the picture isabout 3.6×10⁷ μm².

{circle around (3)} A brightness extraction method in the automatic areameasurement function of the VHX-2000/Ver2.35 software provided byKEYENCE is used.

(a) An automatic area measurement button is clicked.

(b) The brightness extraction method is checked to extract a brightnessregion graph of the picture of the sample.

(c) The option “DARK” in the interface is checked to obtain a pore graphin the picture.

(d) The threshold is adjusted so that the pores of the sample areexactly covered, where the threshold ranges from −80 to +80.

A too large or too small threshold cannot ensure that the actual poresof the sample are covered exactly. When the threshold is too small, themeasured pore area is smaller than the actual area. However, when thethreshold is too large, the measured pore area is larger than the actualarea.

(e) The data of the pore area of the sample is obtained by clicking“NEXT”, and then saved. The standard variance a of the pore area and thepore area distribution center value μ (unit: μm²) of the sample arerecorded.

(2) Coefficient of Variation

{circle around (1)} Coefficient of variation of the pore area of thefabric:

the standard variance σ of the pore area÷the pore area distributioncenter value μ×100%.

{circle around (2)} Coefficient of variation of length of the twistregions in the false-twist direction of the polyester filament:

the coefficient of variation of length of the twist regions in thefalse-twist direction=the standard variance σ of length of the twistregions in the false-twist direction÷the average value μ of length ofthe twist regions in the false-twist direction×100%.

Wherein, a polyester filament having a length of 50 cm is randomlyselected, the length of 20 twist regions in the false-twist direction isthen measured, and finally, the standard variance σ and the averagelength value μ are calculated (the measurement method refers to ┌(7)Ratio of the length of the twist regions in the false-twist direction ofthe polyester filament to the total length of the polyester filament┘hereinafter).

(3) Bending Rigidity

The KES FB2 method is used. (The KES fabric style tester is a fabricstyle tester designed and manufactured by Professor Kawabata Sueo fromthe Kyoto University, where FB2 is a bending performance tester.)

(4) Surface Roughness

The KES FB4 method is used. (The KES fabric style tester is a fabricstyle tester designed and manufactured by Professor Kawabata Sueo fromthe Kyoto University, where FB4 is a friction and surface roughnesstester.)

(5) Compression Energy

The KES FB3 method is used. (The KES fabric style tester is a fabricstyle tester designed and manufactured by Professor Kawabata Sueo fromthe Kyoto University, where FB3 is a compression performance andthickness tester.)

(6) Ratio of the Diameter of the Twist Regions in the False-TwistDirection of the Polyester Filament to the Diameter of the Twist Regionsin the Opposite Direction

Five polyester filaments each having a length of 20 cm in the presentinvention are randomly selected from the fabric, and the diameter of thetwist regions in the false-twist direction and the diameter of the twistregions in the opposite direction of each polyester filament aremeasured by a measurement tool of the KEYENCE digital system by using adigital microscope with a 50× lens from KEYENCE. Five groups of data aremeasured for each polyester filament, the average of specific values ofeach polyester filament is calculated, and the average of the totalspecific values of the five polyester filaments is eventuallycalculated.

(7) Ratio of the Length of Twist Regions in False-Twist Direction of thePolyester Filament to the Total Length of the Polyester Filament

Five polyester filaments each having a length of 50 cm in the presentinvention are randomly selected from the fabric, and a tension of 0.1g/D is applied to each filament. The length of the twist regions in thefalse-twist direction of each filament is measured by EIB-E (model:LAWSON-HEMPHILL, from LAWSON-HEMPHILL). Five groups of data are measuredfor each polyester filament, and the average of the length ratios ofeach polyester filament is calculated. The average of the total lengthratios of the five polyester filaments is eventually calculated.

(8) Softness of the Polyester Filament

By perceptive evaluation from 20 persons, on the basis of the degree ofsoftness of the filament, there are four levels, i.e., Excellent, Good,Pass and Poor. Wherein, if 15 persons or more consider that the filamentis soft, the softness of this filament is Excellent; if 10 to 14 personsconsider that the filament is soft, the softness of this filament isGood; if 5 to 10 persons consider that the filament is soft, thesoftness of this filament is Pass; and, if less than 5 persons considerthat the filament is soft, the softness of this filament is Poor.

The present invention will be further described below by embodiments andcomparison examples.

Embodiment 1

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.13 cm, a coefficient of variation(C.V) of length of 78%, a diameter that is 43% of the diameter of thetwist regions in the opposite direction, and a total length that is31.3% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 2

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 252 dtex and amonofilament number of 278. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 200dtex, a monofilament number of 278 and a monofilament fineness of 0.72dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.10 cm, a coefficient of variation(C.V) of length of 78%, a diameter that is 40% of the diameter of thetwist regions in the opposite direction, and a total length that is22.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 3

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 71 dtex and amonofilament number of 78. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 56dtex, a monofilament number of 78 and a monofilament fineness of 0.72dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.18 cm, a coefficient of variation(C.V) of length of 79%, a diameter that is 55% of the diameter of thetwist regions in the opposite direction, and a total length that is35.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 4

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of232° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.10 cm, a coefficient of variation(C.V) of length of 77%, a diameter that is 39% of the diameter of thetwist regions in the opposite direction, and a total length that is21.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 5

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of245° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.25 cm, a coefficient of variation(C.V) of length of 78%, a diameter that is 54% of the diameter of thetwist regions in the opposite direction, and a total length that is38.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 6

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.6, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.25 cm, a coefficient of variation(C.V) of length of 61%, a diameter that is 56% of the diameter of thetwist regions in the opposite direction, and a total length that is38.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 7

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 2.3, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.10 cm, a coefficient of variation(C.V) of length of 90%, a diameter that is 38% of the diameter of thetwist regions in the opposite direction, and a total length that is21.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 8

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 169 dtex and amonofilament number of 96. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 134dtex, a monofilament number of 96 and a monofilament fineness of 1.40dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.12 cm, a coefficient of variation(C.V) of length of 79%, a diameter that is 40% of the diameter of thetwist regions in the opposite direction, and a total length that is28.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Comparison Example 1

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 40 dtex and amonofilament number of 36. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 28dtex, a monofilament number of 36 and a monofilament fineness of 0.78dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.31 cm, a coefficient of variation(C.V) of length of 78%, a diameter that is 80% of the diameter of thetwist regions in the opposite direction, and a total length that is42.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Comparison Example 2

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 410 dtex and amonofilament number of 288. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 250dtex, a monofilament number of 288 and a monofilament fineness of 0.87dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.08 cm, a coefficient of variation(C.V) of length of 79%, a diameter that is 28% of the diameter of thetwist regions in the opposite direction, and a total length that is18.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Comparison Example 3

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of252° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained false-twisted polyester filament is formed fromalternatingly arranged twist regions in a false-twist direction andtwist regions in an opposite direction, wherein the twist regions in thefalse-twist direction have an average length of 0.35 cm, a coefficientof variation (C.V) of length of 79%, a diameter that is 78% of thediameter of the twist regions in the opposite direction, and a totallength that is 42.0% of the total length of the polyester filament,specifically referring to Table 1.

Comparison Example 4

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of225° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.9, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.06 cm, a coefficient of variation(C.V) of length of 80%, a diameter that is 26% of the diameter of thetwist regions in the opposite direction, and a total length that is18.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Comparison Example 5

Polyester chip material (produced by Toray Fiber(Nantong) Co., Ltd.) isselected and then melt and spun at a speed of 2800 m/min to obtain apolyester pre-oriented yarn POY having a fineness of 128 dtex and amonofilament number of 144. Then, false-twisting is performed accordingto the procedure of FIG. 2 at a speed of 400 m/min, a temperature of238° C. in the first hot box, an extension rate of 1.26 and a D/Y ratioof 1.3, so as to obtain a polyester filament having a fineness of 100dtex, a monofilament number of 144 and a monofilament fineness of 0.69dtex.

The obtained polyester filament is formed from alternatingly arrangedtwist regions in a false-twist direction and twist regions in anopposite direction, wherein the twist regions in the false-twistdirection have an average length of 0.38 cm, a coefficient of variation(C.V) of length of 55%, a diameter that is 68% of the diameter of thetwist regions in the opposite direction, and a total length that is55.0% of the total length of the polyester filament, specificallyreferring to Table 1.

Embodiment 9

55% by weight of common false-twisted polyester yarns in 56 dtex to 78f(produced by Toray Fiber(Nantong) Co., Ltd.) and 45% by weight of thepolyester filaments obtained in Embodiment 3 are knitted by plain stitchon a single-sided circular knitting machine to obtain a grey fabric, andthe grey fabric is then refined (80° C.×20 min), dyed (98° C.×30 min),sized (160° C.×72 s) and fluffed to obtain the cotton-like knittedfabric of the present invention.

The obtained fabric has a pore area distribution centered on 6000 μm², astatistical variability of above 2σ, a coefficient of variation (C.V) ofthe pore area of 41%, a bending rigidity (B) of 0.025 N·cm²/cm, asurface roughness (SMD) of 4.1μ and a compression energy (WC) of 0.35N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 10

55% by weight of common false-twisted polyester yarns in 200 dtex to278f (produced by Toray Fiber(Nantong) Co., Ltd.) and 45% by weight ofthe polyester filaments obtained in Embodiment 2 are knitted by plainstitch on a single-sided circular knitting machine to obtain a greyfabric, and the grey fabric is then refined (80° C.×20 min), dyed (98°C.×30 min), sized (160° C.×72 S) and fluffed to obtain the cotton-likeknitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 15000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 47%, a bending rigidity (B) of 0.015 N·cm²/cm, asurface roughness (SMD) of 3.0μ and a compression energy (WC) of 0.80N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 11

35% by weight of common false-twisted polyester yarns in 100 dtex to144f (produced by Toray Fiber(Nantong) Co., Ltd.) and 65% by weight ofthe polyester filaments obtained in Embodiment 7 are knitted by plainstitch on a single-sided circular knitting machine to obtain a greyfabric, and the grey fabric is then refined (80° C.×20 min), dyed (98°C.×30 min), sized (160° C.×72 S) and fluffed to obtain the cotton-likeknitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 14000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 51%, a bending rigidity (B) of 0.024 N·cm²/cm, asurface roughness (SMD) of 3.8μ and a compression energy (WC) of 0.75N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 12

35% by weight of common false-twisted polyester yarns in 100 dtex to144f (produced by Toray Fiber(Nantong) Co., Ltd.) and 65% by weight ofthe polyester filaments obtained in Embodiment 6 are knitted by plainstitch on a single-sided circular knitting machine to obtain a greyfabric, and the grey fabric is then refined (80° C.×20 min), dyed (98°C.×30 min), sized (160° C.×72 S) and fluffed to obtain the cotton-likeknitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 13000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 48%, a bending rigidity (B) of 0.034 N·cm²/cm, asurface roughness (SMD) of 4.9μ and a compression energy (WC) of 0.30N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 13

100% by weight of the polyester filaments obtained in Embodiment 3 areknitted, in a double-yarn merging manner, by plain stitch on asingle-sided circular knitting machine to obtain a grey fabric, and thegrey fabric is then refined (80° C.×20 min), dyed (98° C.×30 min), sized(160° C.×72 S) and fluffed to obtain the cotton-like knitted fabric ofthe present invention.

The obtained fabric has a pore area distribution centered on 6900 μm², astatistical variability of above 2σ, a coefficient of variation (C.V) ofthe pore area of 58%, a bending rigidity (B) of 0.045 N·cm²/cm, asurface roughness (SMD) of 6.0μ and a compression energy (WC) of 0.20N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 14

100% by weight of the polyester filaments obtained in Embodiment 2 areknitted by plain stitch on a single-sided circular knitting machine toobtain a gray fabric, and the grey fabric is then refined (80° C.×20min), dyed (98° C.×30 min), sized (160° C.×72 S) and fluffed to obtainthe cotton-like knitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 22000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 63%, a bending rigidity (B) of 0.037 N·cm²/cm, asurface roughness (SMD) of 5.1μ and a compression energy (WC) of 0.50N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Embodiment 15

100% by weight of the polyester filaments obtained in Embodiment 8 areknitted by plain stitch on a single-sided circular knitting machine toobtain a grey fabric, and the grey fabric is then refined (80° C.×20min), dyed (98° C.×30 min), sized (160° C.×72 S) and fluffed to obtainthe cotton-like knitted fabric.

The obtained fabric has a pore area distribution centered on 19000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 64%, a bending rigidity (B) of 0.046 N·cm²/cm, asurface roughness (SMD) of 6.3μ and a compression energy (WC) of 0.48N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Comparison Example 6

60% by weight of common false-twisted polyester yarns in 56 dtex to 78f(produced by Toray Fiber(Nantong) Co., Ltd.) and 40% by weight of thepolyester filaments obtained in Embodiment 3 are knitted by plain stitchon a single-sided circular knitting machine to obtain a grey fabric, andthe grey fabric is then refined (80° C.×20 min), dyed (98° C.×30 min),sized (160° C.×72 S) and fluffed to obtain the cotton-like knittedfabric of the present invention.

The obtained fabric has a pore area distribution centered on 4600 μm², astatistical variability of above 2σ, a coefficient of variation (C.V) ofthe pore area of 30%, a bending rigidity (B) of 0.012 N·cm²/cm, asurface roughness (SMD) of 2.1μ and a compression energy (WC) of 0.36N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Comparison Example 7

60% by weight of common false-twisted polyester yarns in 200 dtex to278f (produced by Toray Fiber(Nantong) Co., Ltd.) and 40% by weight ofthe polyester filaments obtained in Embodiment 2 are knitted by plainstitch on a single-sided circular knitting machine to obtain a greyfabric, and the grey fabric is then refined (80° C.×20 min), dyed (98°C.×30 min), sized (160° C.×72 S) and fluffed to obtain the cotton-likeknitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 12000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 35%, a bending rigidity (B) of 0.008 N·cm²/cm, asurface roughness (SMD) of 1.8μ and a compression energy (WC) of 0.85N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Comparison Example 8

55% by weight of common false-twisted polyester yarns in 28 dtex to 36f(produced by Toray Fiber(Nantong) Co., Ltd.) and 45% by weight of thepolyester filaments obtained in Embodiment 1 are knitted by plain stitchon a single-sided circular knitting machine to obtain a grey fabric, andthe grey fabric is then refined (80° C.×20 min), dyed (98° C.×30 min),sized (160° C.×72 S) and fluffed to obtain the cotton-like knittedfabric of the present invention.

The obtained fabric has a pore area distribution centered on 4200 μm², astatistical variability of above 2σ, a coefficient of variation (C.V) ofthe pore area of 27%, a bending rigidity (B) of 0.030 N·cm²/cm, asurface roughness (SMD) of 5.0μ and a compression energy (WC) of 0.18N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Comparison Example 9

55% by weight of common false-twisted polyester yarns in 250 dtex to288f (produced by Toray Fiber(Nantong) Co., Ltd.) and 45% by weight ofthe polyester filaments obtained in Embodiment 2 are knitted by plainstitch on a single-sided circular knitting machine to obtain a greyfabric, and the grey fabric is then refined (80° C.×20 min), dyed (98°C.×30 min), sized (160° C.×72 S) and fluffed to obtain the cotton-likeknitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 25000 μm²,a statistical variability of above 2σ, a coefficient of variation (C.V)of the pore area of 51%, a bending rigidity (B) of 0.007 N·cm²/cm, asurface roughness (SMD) of 1.6μ and a compression energy (WC) of 0.90N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

Comparison Example 10

100% by weight of the polyester filaments obtained in Embodiment 6 areknitted by plain stitch on a single-sided circular knitting machine toobtain a grey fabric, and the grey fabric is then refined (80° C.×20min), dyed (98° C.×30 min), sized (160° C.×72 S) and fluffed to obtainthe cotton-like knitted fabric of the present invention.

The obtained fabric has a pore area distribution centered on 8000 μm², astatistical variability of above 2σ, a coefficient of variation (C.V) ofthe pore area of 25%, a bending rigidity (B) of 0.050 N·cm²/cm, asurface roughness (SMD) of 7.1μ and a compression energy (WC) of 0.15N·cm/cm². The performance parameters of the obtained fabric refer toTable 2.

TABLE 1 Embodiment Embodiment Embodiment Embodiment EmbodimentEmbodiment Distinction 1 2 3 4 5 6 Embodiment 7 POY Spinning speed 28002800 2800 2800 2800 2800 2800 Fineness (dtex) 128 252 71 128 128 128 128Number 144 278 78 144 144 144 144 False-twisting Processing speed(m/min) 400 400 400 400 400 400 400 Temperature in the first hot 238 238238 232 245 238 238 box (° C.) Extension rate (times) 1.26 1.26 1.261.26 1.26 1.26 1.26 D/Y ratio (times) 1.9 1.9 1.9 1.9 1.9 1.6 2.3Polyester Total fineness (dtex) 100 200 56 100 100 100 100 filamentMonofilament fineness (dtex) 0.69 0.72 0.72 0.69 0.69 0.69 0.69 TwistAverage length 0.13 0.10 0.18 0.10 0.25 0.25 0.10 regions (cm) in theCoefficient of 78 78 79 77 78 61 90 false-twist variation of directionlength (%) Ratio to the 43 40 55 39 54 56 38 diameter of the twistregions in the opposite direction (%) Ratio to the total 31.3 22.0 35.021.0 38.0 38.0 21.0 length of the filament (%) Softness Good Good PassGood Pass Pass Excellent Comparison Comparison Comparison ComparisonComparison Distinction Embodiment 8 example 1 example 2 example 3example 4 example 5 POY Spinning speed 2800 2800 2800 2800 2800 2800Fineness (dtex) 169 40 410 128 128 128 Number 96 36 288 144 144 144False-twisting Processing speed (m/min) 400 400 400 400 400 400Temperature in the first hot 238 238 238 252 225 238 box (° C.)Extension rate (times) 1.26 1.26 1.26 1.26 1.26 1.26 D/Y ratio (times)1.9 1.9 1.9 1.9 1.9 1.3 Polyester Total fineness (dtex) 134 23 250 100100 100 filament Monofilament fineness (dtex) 1.40 0.78 0.87 0.69 0.690.69 Twist Average length 0.12 0.31 0.08 0.35 0.06 0.38 regions (cm) inthe Coefficient of 79 78 79 79 80 55 false-twist variation of directionlength (%) Ratio to the 40 80 28 78 26 68 diameter of the twist regionsin the opposite direction (%) Ratio to the total 28.0 42.0 18.0 42.018.0 55.0 length of the filament (%) Softness Poor Poor Excellent PoorExcellent Poor

TABLE 2 Fabric performance Co- Pore efficient Yarn 2 area of Sur- Com-Yarn 1 Total Mono- distri- variation Bending faces pression Total Con-fine- filament bution of the rigidity rough energy Content fineness tentness fineness center pore area (N · cm²/ ness (N Type (%) (dtex) Type(%) (dtex) (dtex) (μm²) (%) cm) (μ) cm/cm²) Embodiment 9 Common 55 56Polyester filament in 45 56 0.72 6000 41 0.025 4.1 0.35 polyesterEmbodiment 3 Embodiment 10 Common 55 200 Polyester filament in 45 2000.72 15000 47 0.015 3.0 0.80 polyester Embodiment 2 Embodiment 11 Common35 100 Polyester filament in 65 100 0.69 14000 51 0.024 3.8 0.75polyester Embodiment 7 Embodiment 12 Common 35 100 Polyester filament in65 100 0.69 13000 48 0.034 4.9 0.30 polyester Embodiment 6 Embodiment 13— — — Polyester filament in 100 56 0.72 6900 58 0.045 6.0 0.20Embodiment 3 Embodiment 14 — — — Polyester filament in 100 200 0.7222000 63 0.037 5.1 0.50 Embodiment 2 Embodiment 15 — — — Polyesterfilament in 100 134 1.40 19000 64 0.046 6.3 0.48 Embodiment 8 ComparisonCommon 60 56 Polyester filament in 40 56 0.72 4600 30 0.012 2.1 0.36example 6 polyester Embodiment 3 Comparison Common 60 200 Polyesterfilament in 40 200 0.72 12000 35 0.008 1.8 0.85 example 7 polyesterEmbodiment 2 Comparison Common 55 28 Polyester filament in 45 28 0.784200 27 0.030 5.0 0.18 example 8 polyester comparison example 1Comparison Common 55 250 Polyester filament in 45 250 0.87 25000 510.007 1.6 0.90 example 9 polyester comparison example 2 Comparison — — —Polyester filament in 100 100 0.69 8000 25 0.050 7.1 0.15 example 10comparison example 5

It can be seen from Table 1 that:

(1) It can be seen from Embodiments 1, 2 and 3 that, if the totalfineness is higher, the average length of the twist regions in thefalse-twist direction is shorter, the proportion of the twist regions inthe false-twist direction in the filament is lower, and the ratio of thediameter of the twist regions in the false-twist direction to thediameter of the twist regions in the opposite direction is smaller.However, the coefficient of variation of length basically remainsunchanged.

(2) It can be seen from the Embodiments 1, 4 and 5 that, when the samepolyester pre-oriented yarn POY is processed at a same false-twistingspeed, a same extension rate and a same D/Y ratio, if the temperature inthe first hot box is higher, the average length of the twist regions inthe false-twist direction of the polyester filament becomes largerrelatively, the proportion of the twist regions in the false-twistdirection in the filament is higher, and the ratio of the diameter ofthe twist regions in the false-twist direction to the diameter of thetwist regions in the opposite direction is larger. However, thecoefficient of variation of length is close to each other.

(3) It can be seen from the Embodiments 1, 6 and 7 that, when the samepolyester pre-oriented yarn POY is processed at a same false-twistingspeed, a same temperature in the first hot box and a same extensionrate, if the D/Y ratio is higher, the average length of the twistregions in the false-twist direction of the polyester filament issmaller, the proportion of the twist regions in the false-twistdirection in the filament is lower, the ratio of the diameter of thetwist regions in the false-twist direction to the diameter of the twistregions in the opposite direction is smaller, the coefficient ofvariation of length is larger, and the yarn is softer.

(4) It can be seen from Embodiment 8 that, when the monofilamentfineness is greater than 1.3 dtex, the yarn feels worse even if theappearance and various performance indexes of the yarn are similar tothose of the cotton yarn.

(5) It can be seen from Embodiments 1 and 2 that, when the totalfineness of the polyester filament is too small or too large, theappearance and performances similar to those of the cotton yarn cannotbe obtained. If the total fineness is too small, the full-stiffpolyester yarn will be caused; however, if the total fineness is toolarge, the common polyester false-twisted yarn is formed.

(6) It can be seen from the comparison example 3 that, when thetemperature in the first hot box is greater than 250′C, the yarn iscompletely stiff. It can be seen from the comparison example 4 that,when the temperature in the first hot box is less than 230° C., the yarnis too fluffy, similar to the common polyester false-twisted yarn.

(7) It can be seen from the comparison example 5 that, when the D/Yratio is less than 1.5, the appearance and performances similar to thoseof the cotton yarn cannot be realized, and the yarn is stiff.

It can be seen from Table 2 that:

(1) It can be seen from Embodiments 9 and 13 and Embodiments 10 and 14that, at the same fineness, if the content of the yarn 2 increases, thefabric has a larger pore area, a larger coefficient of variation of thepore area distribution, a higher bending rigidity, a higher surfaceroughness, and a lower compression energy. That is, the cotton-likeeffect is improved.

(2) It can be seen from Embodiments 11 and 12 that, if the yarn 2 has asmaller diameter ratio and a larger coefficient of variation of lengthof the twist regions in the false-twist direction, the fabric has alarger pore area and a larger coefficient of variation of the pore area,i.e., a more non-uniform pore area distribution. In addition, if thetwist regions in the false-twist direction have a smaller length and alower proportion, the fabric has an increased softness, a decreasedbending rigidity, a decreased surface roughness, and an increasedcompression energy. That is, the fluffiness is increased.

(3) It can be seen from Embodiments 9 and 10 that, if the yarn 2 has alarger fineness and a smaller diameter ratio, the fabric has a largerpore area and a larger coefficient of variation of the pore area, i.e.,a more non-uniform pore area distribution. If the twist regions in thefalse-twist direction has a smaller length and a lower proportion, thefabric has a lower bending rigidity, a lower surface roughness, and alower compression energy. That is, the fluffiness is higher.

(4) It can be seen from Embodiment 15 that, although the fabric has apore distribution similar to that of the cotton-containing products, thefabric has a higher surface roughness which influences the cotton-likeeffect since the monofilament fineness of the yarn 2 is greater than 1.3dtex.

(5) It can be seen from Embodiments 6 and 7 that, when the content ofthe yarn 2 is less than 45%, the same coefficient of variation of thepore area as the cotton-containing products cannot be realized, so thatthe same appearance as the cotton products is not achieved.

(6) It can be seen from the comparison example 8 that, since the usedyarn 2 is a common full-stiff polyester yarn, the fabric is unable tohave the same appearance as the cotton-containing products (both thepore area and the coefficient of variation of the pore area are toosmall); moreover, the fabric has a too low fluffiness and is thus not sosoft as cotton products.

(7) It can be seen from the comparison example 9 that, the used yarn 2is similar to a common full-stiff polyester yarn, and the fabric has atoo large pore area and has no compactness like the cotton products.Moreover, the fabric has an insufficient bending rigidity and does nothave the same slenderness as the cotton products.

(8) It can be seen from the comparison example 10 that, since the usedyarn 2 does not have the appearance and performances similar to those ofthe cotton yarn, the fabric has a too uniform pore distribution and doesnot have the same appearance as the cotton products. Moreover, thebending rigidity is too high, and it is thus not so soft as cottonproducts.

1. A cotton-like knitted fabric, wherein the fabric is a weft-knittedfabric obtained by material containing at least above 45% by weight ofpolyester filaments; and, the pore area distribution of the fabric iscentered on 6000 to 22000 μm² and has a statistical variability of above2σ, and the coefficient of variation of the pore area is greater than40%.
 2. The cotton-like knitted fabric according to claim 1, wherein thecontent of the polyester filament is 100% by weight.
 3. The cotton-likeknitted fabric according to claim 1, wherein the polyester filament isformed from alternatingly arranged twist regions in a false-twistdirection and twist regions in an opposite direction, wherein the twistregions in the false-twist direction have an average length of less than0.3 cm, a coefficient of variation of length above 60%, a diameter thatis 30% to 70% of the diameter of the twist regions in the oppositedirection, and a total length that is 20.0% to 40.0% of the total lengthof the polyester filaments.
 4. The cotton-like knitted fabric accordingto claim 1, wherein the polyester filament has a total fineness of 56 to220 dtex, and a monofilament fineness of less than 1.30 dtex.
 5. Thecotton-like knitted fabric according to claim 1, wherein the fabric is apile fabric.
 6. The cotton-like knitted fabric according to claim 1,wherein the fabric is obtained by knitting a single filament or jointlyknitting two filaments.
 7. The cotton-like knitted fabric according toclaim 1, wherein the fabric has a bending rigidity of 0.015 to 0.045N·cm²/cm, a surface roughness of 3.0 to 6.0μ, and a compression energyof 0.20 to 0.80 N·cm/cm².
 8. A polyester filament, wherein the polyesterfilament is formed from alternatingly arranged twist regions in afalse-twist direction and twist regions in an opposite direction,wherein the twist regions in the false-twist direction have an averagelength of less than 0.3 cm, a coefficient of variation of length ofabove 60%, a diameter that is 30% to 70% of the diameter of the twistregions in the opposite direction, and a total length that is 20.0% to40.0% of the total length of the polyester filament.
 9. The polyesterfilament according to claim 8, wherein the polyester filament has atotal fineness of 56 to 220 dtex, and a monofilament fineness of lessthan 1.30 dtex.
 10. A method for manufacturing the polyester filamentaccording to claim 8, comprising the following steps of: leading apolyester pre-oriented yarn into a first roller, then into a first hotbox for heating, and finally into a false twister, a second roller, asecond hot box and a third roller to obtain the polyester filament,wherein the temperature in the first hot box is 230° C. to 250° C.; and,the D/Y ratio in the step is 1.5 to 2.5.